/*
Copyright (c) 2008, Arturo José Guédez Romero

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
    * Neither the name of Cultusoft nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package com.cultusoft.groovin.plugins.changetracker;

class ChecksumVerifier {

  def hashedFileExtension = ".md5"
      
  def wantedExtensions = [".java", ".hbm.xml", ".jsp", ".html"] as List
      
  def project
  def checkSumLocation = "groovinCheckSum"
  
  public boolean verifyAndUpdateChecksumForDirectory(def directory) {
      return updateFilesInDirectory(directory)
  }
  
  private boolean updateFilesInDirectory(def directory) {
      def haveFilesChangedSinceLastBuild = false;
      
      def files = directory.listFiles()
      for (file in files) {
          if (file.isDirectory()) {
              haveFilesChangedSinceLastBuild |= updateFilesInDirectory(file)
          } else {
              haveFilesChangedSinceLastBuild |= updateSingleFile(file)
          }
      }
      
      return haveFilesChangedSinceLastBuild
  }
  
  private boolean updateSingleFile(def file) {
      if ( !isFileExtensionInWantedSet(file) ) {
          return false
      }
      
      def oldCheckSum = getOldCheckSum(file)
      def newCheckSum = new MD5Generator().md5File(file)
      
      def hasFileChanged  = !newCheckSum.equals(oldCheckSum)
      if (hasFileChanged) {
    	  writeNewCheckSum(file, newCheckSum)
      }
      
      return hasFileChanged
  }
  
	private void writeNewCheckSum(def file, def newCheckSum) {
		def checkSumFile = getCheckSumFile(file) 
        BufferedWriter out = new BufferedWriter(new FileWriter(checkSumFile.getPath()));
        out.write(newCheckSum);
        out.close();
	}
	private String getOldCheckSum(def file) {
		def checkSumFile = getCheckSumFile(file) 
		
		if (!checkSumFile.exists()) { 
			return null
		}
			
	    BufferedReader reader = new BufferedReader(new FileReader(checkSumFile.path));
	    def oldCheckSum = reader.readLine()
	    reader.close();
	    return oldCheckSum
  	}
	
	private def getCheckSumFile(def file) {
      def rootDirectory = new File(project.directory, checkSumLocation) ;
      if (!rootDirectory.exists()) {
    	  rootDirectory.mkdirs();
      }
      
      def checkSumDestinationDirectory = new File(rootDirectory, file.parentFile.path)
      if (!checkSumDestinationDirectory.exists()) {
    	  checkSumDestinationDirectory.mkdirs();
      }
      
      return new File(checkSumDestinationDirectory, file.name + hashedFileExtension)
	}
  
	private boolean isFileExtensionInWantedSet(def file) {
		def filePath = file.getPath()
      
		for (wantedExtension in wantedExtensions) {
			if (filePath.endsWith(wantedExtension)) {
				return true;
			}
		}
		return false;
	}

}